Methicillin-Resistant <i>Staphylococcus aureus</i> Isolated from Central Region of Iran: Antibiotic Resistance and <i>SCCmecA</i> Types

Abstract

Background: Staphylococcus aureus is known as one of the bacteria causing a wide range of nosocomial infections. Objectives: This study aimed to investigate the frequency of methicillin-resistant S. aureus (MRSA) in clinical specimens using phenotypic and molecular methods and to evaluate the types of staphylococcal cassette chromosome mec (SCCmec). Methods: In this descriptive-analytical study, 230 S. aureus isolates were obtained from various clinical samples from six therapeutic and diagnostic centers in Yazd, Iran (Shahid Sadoughi, Afshar, Shahid Rahnemoon, Shohadaye Kargar, Shohadaye Mehrab Hospitals, and the central laboratory) between November 2021 and June 2022. The antibiotic resistance of all isolates was determined using the disk diffusion method. Methicillin-resistant S. aureus strains were identified through cefoxitin disc diffusion. Additionally, the femA and panton-valentine leukocidin (PVL) genes, as well as SCCmecA types, were determined using specific primers via conventional PCR and multiplex PCR methods. Results: All isolates were positive for the femA gene, and 78 (33.9%) isolates were identified as MRSA. Erythromycin exhibited the highest resistance rate at 83.3%, followed by tetracycline at 56.4%. Among the MRSA isolates, 29.5% contained the PVL gene. Furthermore, 59 isolates (75.6%) were identified as SCCmec type IV, while 11.5% (9) were type III, 10.3% (8) were type V, and 6.2% (2) were type I. Conclusions: This study found that 33.9% of the isolates were identified as MRSA, with a high erythromycin resistance rate of 83.3%. SCCmec type IV predominated at 75.6%. These findings emphasize the need for ongoing surveillance and targeted strategies to manage MRSA and its resistance patterns, especially in light of the increasing prevalence of community-acquired MRSA (CA-MRSA) in therapeutic centers across Iran.